Question

What is the method to remove temporary hardness of water?

• A. Ion exchange method
• B. Distillation method
• C. Boiling method
• D. Clark's method

Hint:

Clark's method is effective for removing temporary hardness by precipitating calcium and magnesium bicarbonates as their carbonates.

Answer 1

The Correct Option is D

Clark's method is used to remove temporary hardness of water. Temporary hardness is caused by the presence of dissolved bicarbonates of calcium and magnesium, which can be removed by heating the water. When heated, the bicarbonates decompose to form insoluble carbonates, which precipitate out of the water. Clark's method involves adding slaked lime (Ca(OH)$_2$) to the water to convert these bicarbonates into carbonates.